1. Field of the Invention
Exemplary embodiments of the present invention relate to a thin film transistor and a method for forming a trench, a method for forming a metal wire, and a method for manufacturing a thin film transistor array panel. More particularly, exemplary embodiments of the present invention relate to a thin film transistor and a method for forming a trench with reduced residual particles and a residual film in the trench, a method for forming a metal wire, and a method for manufacturing a thin film transistor array panel.
2. Discussion of the Background
A thin film transistor (TFT) is typically used as a switching element for independently driving each pixel in a flat panel display such as a liquid crystal display or an organic light emitting diode display. The thin film transistor array panel includes a thin film transistor, a pixel electrode that is connected thereto, a gate line that transmits a gate signal to the thin film transistor, and a data line that transmits a data signal.
The thin film transistor includes a gate electrode connected with a gate line to receive a gate signal, a semiconductor layer formed on the gate electrode, a source electrode connected with a data line to receive a data signal, and a drain electrode formed spaced apart from the source electrode and connected with the pixel electrode. In this case, the gate line, the gate electrode, the data line, the source electrode, and the drain electrode are made of metal wires.
In order to increase resolution, research and development have been conducted to increase pixel integration per unit area in the thin film transistor array panel, and for high-speed image signal processing, research and development have been made on using oxide semiconductor having high electron mobility or a low-resistive copper wire.
In such case, an insulating layer of several micrometers is deposited and a trench is formed, and then a cooper wire is formed in the trench to realize a low-resistive copper wire. When a photo etching process using a conventional photosensitive film is used to form the trench, the selectivity is significantly decreased.
Recently, research and development have been conducted on etching using a metal mask rather than using a photosensitive film, but use of the metal mask may cause generation of residual particles in the trench and the etching may not reach the bottom of the trench such that a residual film remains.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.